The expression of EGF receptors, EGF-like factors and c-myc in ovarian and cervical carcinomas and their potential clinical significance.

The expression of the epidermal growth factor receptor (EGF-R) and the c-myc oncogene was investigated in different specimens of ovarian and cervical carcinomas. The EGF-Rs were analyzed by EGF binding assay, immunohistochemistry and Northern blotting. For analysis of c-myc expression, we used Northern blotting and immunohistochemistry. Furthermore, tissue concentrations of EGF-like factors (EGF-F) were measured in the same tumor and non-malignant specimens. The biochemical determination of EGF-R demonstrated that EGF specific binding sites were detected in 36% of ovarian (n = 140) and 81% of cervical carcinomas (n = 42). High amounts of EGF-R (greater than 10 fmol/mg specific binding) were found in 8% of the ovarian and 41% of the cervical carcinomas. Increased expression of EGF-R specific mRNA was detectable in 7/21 ovarian and in 5/7 cervical carcinomas. A positive correlation between the amounts of EGF-R mRNA, the EGF-R binding data and the staining index of EGF-R immunohistochemistry was found. The EGF-R immunohistochemistry demonstrates that only the tumor cells produce increased amounts of EGF-R, while the stromal cells are EGF-R negative. Low amounts of EGF-R specific mRNA were also detected in biochemically EGF-R negative tumors. The c-myc specific mRNA signal was found in all cases investigated. It is shown that the c-myc expression was increased in 10/21 ovarian and 5/7 cervical carcinomas. There was no positive correlation between the amounts of EGF-R and c-myc mRNAs. The product of myc, as detected by immunohistochemistry, is found in tumor as well as in stromal cells. The levels of EGF-F were measured in extracts of 63 ovarian and 12 cervical carcinomas and in 21 non-malignant tissues. About 30% of the tumor extracts contained higher EGF-F levels (4-15 ng/mg) than those found in the non-malignant specimens. Tumors with high EGF-F levels expressed high amounts of c-myc RNA. The EGF-R status (n = 111) and the EGF-F levels (n = 63) were related to the prognosis of survival for patients with ovarian carcinomas. EGF-R positive (EGF-R(+)) ovarian carcinomas had a significantly higher response rate to chemotherapy. The survival time of the EGF-R(+) group is reduced compared to the EGF-R negative (EGF-R(-)) group if only patients in remission are used to construct survival curves. Furthermore, a poor prognosis for survival was noticed for ovarian carcinoma patients with high EGF-F levels.